A comprehensive examination of the local- and long-range structure of Sb(6)O(13) pyrochlore oxide

The crystal structure of the Sb(6)O(13) oxide, exhibiting a defect pyrochlore crystal structure with atomic vacancies, has been studied using a complete set of state-of-the-art techniques. The degree of antimony disproportionation in Sb(3+) and Sb(5+) valence states has been directly determined around 36% and 64%, respectively, using X-ray absorption near edge structure (XANES). These findings are in excellent agreement with our Rietveld analysis of synchrotron X-ray (SXRD) and neutron powder diffraction (NPD) results. Moreover, the highly distorted Sb(3+) coordination due to its lone electron pair has been critically revisited. The bonding distances and coordination of Sb(3+) and Sb(5+) species closely agree with an extensive dynamic and crystallographic determination using the Extended X-ray Absorption Fine Structure (EXAFS) technique. Most importantly, the specific local disorder of the two distinctive Sb ions has been crosschecked monitoring their unusual Debye–Waller factors.